Can a module be provided for use with Jan.ai as a provider?

Yes, it can. LLM provider have been recently incorporated to https://www.drupal.org/project/ai → module.
This is a list of providers it already has: https://git.drupalcode.org/project/ai/-/tree/1.0.x/modules/providers?ref...
To include jan.ai as well, one has to copy one of these modules and modify to jan.ai specifications, then release it as a new module.
Another option is discuss this in this issue: 📌 [meta] Discussion: what LLM providers to include Active

Ticket has been answered - no further development will be done in this module, it has been deprecated in favour of AI → module.